Hair treatment method

Abstract

A hand held device generates a predetermined number of pulses of light having a predetermined electromagnetic spectrum, a predetermined duration, a predetermined inter-pulse interval, and a predetermined total energy. The pulse sequence is delivered to a skin surface to stimulate hair growth by energizing the hair follicles. The light may be absorbed by endogenous chromophores of the dermal tissues and/or by exogenous chromophores delivered to the dermal tissues. The device is used periodically to apply the pulses of light to the selected skin surface at total energy levels per session that are much lower than the energies used in hair removal treatments.

1 . A hair treatment method comprising: 
 generating a predetermined number of pulses of light each having a predetermined electromagnetic spectrum extending over a range of wavelengths;    directing said pulses of light towards a skin surface on which it is desired to grow hair, said pulses having at least one pulse duration and a total energy all predetermined to stimulate growth of hair along said skin surface; and    at least in part owing to the applying of said pulses to respective dermal tissues of said skin surface, stimulating follicles in said respective dermal tissues to grow hair.    
   
   
       2 . The method defined in  claim 1  wherein said total energy is less than approximately 20 Joules of energy per square centimeter of said skin surface.  
   
   
       3 . The method defined in  claim 2  wherein said number of pulses is greater than one, said pulses having an inter-pulse interval of at least 300 msec approximately.  
   
   
       4 . The method defined in  claim 3  wherein said duration is between approximately 1 msec and approximately 2 seconds.  
   
   
       5 . The method defined in  claim 4  wherein said spectrum includes wavelengths between about 300 nm and 1200 nm.  
   
   
       6 . The method defined in  claim 2  wherein said total energy is between approximately 0.01 Joules and approximately 10 Joules of energy per square centimeter of said skin surface.  
   
   
       7 . The method defined in  claim 1  wherein said range of wavelengths includes at least one wavelength absorbable by a chromophore endogenous to said dermal tissues.  
   
   
       8 . The method defined in  claim 7  wherein said dermal tissues include dermal blood vessels and wherein said chromophore is hemoglobin.  
   
   
       9 . The method defined in  claim 1  wherein the light of said pulses is incoherent.  
   
   
       10 . The method defined in  claim 1 , further comprising applying an exogenous chromophore to said skin surface prior to the directing of said pulses towards said skin surface, said pulses of light including at least one wavelength absorbable by said exogenous chromophore.  
   
   
       11 . The method defined in  claim 1 , further comprising disposing a template or mask along said skin surface prior to the directing of said pulses of light towards said skin surface, and maintaining said template or mask disposed along said skin surface during the directing of said pulses of light towards said skin surface.  
   
   
       12 . The method defined in  claim 1  wherein said number of pulses are generated in a plurality of sets, at respective times, the directing of said pulses of light towards said skin surface including directing of the pulses of said sets towards said skin surface at said respective times, thereby effectuating multiple passes over said skin surface.  
   
   
       13 . A hair treatment method comprising: 
 generating first pulses of light each having a predetermined electromagnetic spectrum extending over a range of wavelengths;    directing said first pulses of light towards a first skin area on which it is desired to grow hair, said first pulses being defined by a first set of parameters including number of pulses, pulse duration and total energy;    generating second pulses of light each having a predetermined electromagnetic spectrum extending over a range of wavelengths;    directing said second pulses of light towards a second skin area on which it is desired to grow hair, said second pulses being defined by a second set of parameters including number of pulses, pulse duration and total energy;    comparing hair growth along said first skin area with hair growth along said second skin area to determine which of said first set of parameters and said second set of parameters is a relatively optimal set of parameters for stimulating hair growth;    subsequently generating third pulses of light each having a predetermined electromagnetic spectrum extending over a range of wavelengths; and    directing said second pulses of light towards said first skin area and said second skin area, said third pulses being defined by said optimal set of parameters.    
   
   
       14 . The method defined in  claim 13  wherein at least one of said first set of parameters and said second set of parameters includes a number of pulses greater than one, said one of said first set of parameters and said second set of parameters including an inter-pulse interval between 1 msec and 2 seconds.  
   
   
       15 . The method defined in  claim 13  wherein said inter-pulse interval is greater than approximately 300 msec.  
   
   
       16 . The method defined in  claim 13  wherein said first set of parameters and said second set of parameters each include a total energy of less than approximately 20 Joules of energy per square centimeter of said skin surface.  
   
   
       17 . The method defined in  claim 13  wherein said first set of parameters and said second set of parameters each include a total energy between approximately 0.01 Joules and approximately 10 Joules of energy per square centimeter of said skin surface.  
   
   
       18 . The method defined in  claim 13  wherein said first set of parameters and said second set of parameters each include a pulse duration between approximately 1 msec and approximately 2 seconds.  
   
   
       19 . The method defined in  claim 13  wherein said dermal tissues contain at least one type of chromophore absorbable by said first pulses of light, said second pulses of light and said third pulses of light, said chromophore being endogenous to said dermal tissues.  
   
   
       20 . The method defined in  claim 19  wherein said dermal tissues include dermal blood vessels and wherein said chromophore is hemoglobin.  
   
   
       21 . The method defined in  claim 13  wherein the light of said pulses is incoherent.  
   
   
       22 . The method defined in  claim 13  wherein said first skin area and said second skin area are disposed proximately to one another, further comprising disposing a template to define said first skin area and said second skin area during the directing of said first pulses of light and said second pulses of light, also comprising disposing said template during the comparing of hair growth along said first skin area with hair growth along said second skin area.  
   
   
       23 . A device for applying light energy to a skin surface, comprising: 
 a housing;    a light source disposed in said housing;    an applicator interface element mounted to said housing for guiding light from said source to the skin surface, said applicator interface element including a hydrogel material.    
   
   
       24 . The device defined in  claim 23  wherein said applicator interface element includes a block of the hydrogel material.  
   
   
       25 . The device defined in  claim 23  wherein said applicator interface element includes a polymeric envelope containing a fluid including particles of the hydrogel material.  
   
   
       26 . The device defined in  claim 23  wherein the light source is in contact with the hydrogel material.